Internships typically involve some sort of final interview towards the end. For some firms, this interview is as important as any other element of the assessment (if not more important), whereas other firms might treat it more as a casual debrief. Either way, by the time this interview comes around, your motivation for wanting to join the firm should be fully formed and well-articulated.

Whilst three or four structured reasons for wanting to work for a particular firm may scrape you through an interview before an internship, much more may be expected of you in an end-of-internship interview. Having spent a number of weeks immersed in a firm's culture, meeting various employees and engaging in real work, your reasons for wanting to work at the firm will have to be more personal, more substantive and less derivative of the firm’s marketing materials.

Ask yourself how your impression of the firm has evolved over the course of the internship. Were any of your preconceptions confirmed or dispelled? Were there people you particularly enjoyed meeting? If so, what was it about those people? Does the culture really resonate with you? If so, describe the culture and why it appeals. Did you learn more about the training on offer and if so, did this help to differentiate the firm from its competitors? Were there pieces of work that you found particularly interesting or engaging? Be prepared to discuss the work you completed in detail, including what you enjoyed about it and how it fit into the wider context of the relevant matters. 

Prepare some carefully considered questions for your interviewers. These might relate to your interviewer’s career and motivations, or the firm’s culture, its future strategies, the challenges it is facing (or may face in the future), its training or anything else you can think of that demonstrates your genuine interest in working there. If you do plan on asking about the firm’s challenges and future strategies, make sure you have carried out some related research, as you may well be asked to express a personal opinion. 

Also be prepared to give feedback. What have you enjoyed? What did you not enjoy so much? How could the internship be improved? How does the firm compare to other firms you have interned at? Has your opinion of the firm changed since your internship commenced? Did the internship match up to your prior expectations and preconceptions?